Ok if the wiring is fine and the heater checks out ok then this is more then likely the control board at fault.
Take the control board out from inside the door and make a note of were the wires go.
Then pull the wires off and open the plastic casing.
From there remove the board and inspect it and see if theres any burn marks or dry joints. If so then you need to resolder it and that should sort it. As on these you can get a dry joint on the heater relay and this stops the heat.
If that's ok then a faulty tacho on the motor can also cause it not to heat.
Look at the wash motor and you will see 4 wires. Locate the 2 black or red wires going to the tacho at the back of the motor and test the resistance there. If its open circuit (no reading) then the motor is faulty. But if that's ok and the heater and wiring is fine then the control board will be the fault and will need to be replaced.
If you need anymore info just get back to me.
The Motor is working ok as the machine does the wash but doesn't heat the water. I had a look at the control board and there doesn't seem to be any burn marks on it.
The motor will work fine but if the tacho is open circuit it was at full speed and skips the heat phase.
Its not a common fault but I have come across it a few times were ive checked the heater and wiring and replaced the control board and it turned out to be the motor tacho.
But if the tacho is fine and every thing else is then the heater relay on the board will be the fault here. Even if theres no burn marks and can still be faulty im afraid.
Ok. I will check it out over the next couple of days and let you know how I get on.
Ok no worries speak soon.